5.5 Steam Online Subsystem lobby issue

This has been fixed.

in your Join Session function

FOnlineSessionSearchResult NewSession = Session;
NewSession.Session.SessionSettings.bUseLobbiesIfAvailable = true;
NewSession.Session.SessionSettings.bUsesPresence = true;

and pass NewSession in to IOnlineSessionPtr->JoinSession()

This forces bUseLobbiesIfAvailable to be true